Laser reflecting cavity with ASE suppression and heat removal

Abstract

A thermally conducting reflecting envelope for use in laser cavities, and laser apparatus employing such envelopes. A transparent heat conducting member, such as sapphire, surrounds a laser medium and has a transmissive coating thereon that transmits pump light provided by a pump light source onto the laser medium. The coating reflects the diode pump light and transmits laser light to suppress ASE that causes clamping of the laser output at a relatively low level. An absorbing elastic material is disposed on the dielectric coating and is adapted to absorb the laser light. Heat sinks are disposed in contact with the absorbing elastic material, and conducts heat away from the laser medium. A light entrance window or area is antireflection coated to transmit the pump light onto the laser medium. A liquid cooled version further includes a liquid cooling channel disposed between the laser medium and the thermally conducting member. Two slab lasers are also disclosed employing the present thermally conducting reflecting envelope. The present invention provides more efficient cooling and a more effective ASE suppression than conventional Samarium glass filters in solid state lasers pumped by flashlamps or laser diodes. The present invention provides for efficient heat conduction and removal from a laser medium, efficient transmission and absorption of laser light to suppress ASE, and efficient transmission of pump light to the laser medium.

What is claimed is: 
     
       1. Laser apparatus comprising: a laser medium adapted to provide laser light;   a pump light source for providing pump light to said laser medium;   a thermally conducting transparent member disposed adjacent to said laser medium and having an entrance window disposed adjacent said pump light source;   an optically transmitting antireflecting coating disposed on said thermally conducting transparent member that transmits said pump light provided by said pump light source that is transmitted to said laser medium through said entrance window of said thermally conducting transparent member;   a dielectric coating disposed on said thermally conducting transparent member that reflects said pump light and transmits said laser light to suppress amplified stimulated emission;   an absorbing elastic material disposed on the outer surface of said thermally conducting transparent member around said dielectric coating that is adapted to absorb said laser light; and   a heat sink disposed in contact with said absorbing elastic material to conduct heat away from said laser medium.   
     
     
       2. The laser apparatus of claim 1 wherein said thermally conducting transparent member is comprised of sapphire. 
     
     
       3. The laser apparatus of claim 1 wherein said laser medium comprises a laser rod. 
     
     
       4. The laser apparatus of claim 1 wherein said laser medium comprises a laser slab. 
     
     
       5. The laser apparatus of claim 1 wherein said laser medium comprises a Nd:YAG laser medium and wherein said dielectric coating is adapted to reflect 800 nm pump light and transmit 1.06 μm laser light. 
     
     
       6. The laser apparatus of claim 1 wherein said entrance window has an antireflection coating disposed thereon that is adapted to transmit said pump light through said thermally conducting transparent member and onto said laser medium. 
     
     
       7. The laser apparatus of claim 1 further comprising a liquid cooling channel disposed between said laser medium and said thermally conducting transparent member. 
     
     
       8. The laser apparatus of claim 1 further comprising an air gap disposed between said laser medium and said thermally conducting transparent member. 
     
     
       9. The laser apparatus of claim 1 further comprising an elastic member disposed between said laser medium and said thermally conducting transparent member. 
     
     
       10. Laser apparatus comprising: a laser medium adapted to provide laser light;   a pump light source for providing pump light to said laser medium;   a thermally conducting transparent member disposed adjacent to said laser medium and having an entrance window disposed adjacent said pump light source;   a liquid cooling channel disposed between said laser medium and said thermally conducting transparent member;   an optically transmitting antireflecting coating disposed on said thermally conducting transparent member that transmits said pump light provided by said pump light source that is transmitted to said laser medium through said entrance window of said thermally conducting transparent member;   a dielectric coating disposed on said thermally conducting transparent member that reflects said pump light and transmits said laser light to suppress amplified stimulated emission;   an absorbing elastic material disposed on the outer surface of said thermally conducting transparent member around said dielectric coating that is adapted to absorb said laser light; and   a heat sink disposed in contact with said absorbing elastic material to conduct heat away from said laser medium.   
     
     
       11. The laser apparatus of claim 10 wherein said thermally conducting transparent member is comprised of sapphire. 
     
     
       12. The laser apparatus of claim 10 wherein said laser medium comprises a laser rod. 
     
     
       13. The laser apparatus of claim 10 wherein said laser medium comprises a laser slab. 
     
     
       14. The laser apparatus of claim 10 wherein said laser medium comprises a Nd:YAG laser medium and wherein said dielectric coating is adapted to reflect 800 nm pump light and transmit 1.06 μm laser light. 
     
     
       15. The laser apparatus of claim 10 wherein said entrance window has an antireflection coating disposed thereon that is adapted to transmit said pump light through said thermally conducting transparent member and onto said laser medium. 
     
     
       16. Laser apparatus comprising: a pump light source;   a laser medium;   two layers of transparent elastic material disposed on opposite surfaces of said laser medium.   an air gap disposed around the lateral edges of said laser medium sufficient to provide for heat transfer;   a thermally conducting transparent member disposed between a first layer of said transparent elastic material and said pump light source;   a heat sink disposed around the periphery of said laser medium and coupled to said thermally conducting transparent member to conduct heat away from said laser medium; and   a dielectric coating disposed around a predetermined portion of the periphery of said laser medium.   
     
     
       17. The laser apparatus of claim 16 wherein said thermally conducting transparent member is comprised of sapphire. 
     
     
       18. The laser apparatus of claim 16 further comprising: first and second thermally conducting transparent members respectively disposed in contact with said two layers of transparent elastic material to form a sandwich structure, wherein said first thermally conducting transparent member is disposed adjacent said pump light source and has an antireflection coating disposed thereon, and wherein said second thermally conducting transparent member has a dielectric coating to provide reflectance of said pump light and transmission of said laser light; and   an absorbing elastic material disposed on an outer surface of said second thermally conducting transparent member opposite from said pump light source that is adapted to absorb said laser light.   
     
     
       19. The laser apparatus of claim 16 wherein said laser medium comprises a Nd:YAG laser medium and wherein said dielectric coating is adapted to reflect 800 nm pump light and transmit 1.06 μm laser light.